<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>径向渐变</title>
  <style type="text/css">
    p{
      width: 200px;
      height: 200px;
      border-radius: 50%;
      background-image: radial-gradient(ellipse at center,red,purple);
    }
  </style>
</head>
<body>
<p></p>
</body>
</html>